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Discussion Starter · #1 · (Edited)
Having trouble adding a clutch stop to your E46?

Midway through the 2001 model year, BMW changed the design of the clutch
master cylinder, removing the externally mounted starter interlock switch,
and incorporating it into the master cylinder itself. The result is that it
has become much more difficult to modify or bypass the starter interlock
switch.

Difficult, but not impossible.

Below is a picture of the older style master cylinder (top), and the newer
style master cylinder with the interlock with integral interlock switch
(bottom). Pictured between them is a retrofit harness.

<img src="http://www.uucmotorwerks.com/images/CDV1.jpg"

This next picture shows the new style master cylinder disassembled. At the
bottom of the "plunger" is a magnet, which is what is responsible for
telling the interlock switch that the clutch is depressed. The magnet can be
removed, or fooled with another magnet, but this will in turn also defeat
the cruise control safety interlock. Not good.

<img src="http://www.uucmotorwerks.com/images/CDV2.jpg">

Now let's turn our attentoin back to that retrofit harness. That harness
exists for one reason: there is no set cut-off date for when the newer style
master cylinder was first added to the E46, nor for when an older car should
not be equipped with it. So your dealer has the ability to retrofit the
newer master cylinder to your E46 with that plug-and-play harness.

The solution is simple, but not cheap: the older style master cylinder and
interlock switch can be retrofitted. There is no factory harness for this
retrofit, so you'd have to do the wiring yourself. Then you can perform the standard interlock modification to make your clutch stop work.

I'll be the first to admit that this is a lot of work to do simply to
install a $20 part. But UUC knows there are some fanatics who will be
interested in making the swap, and countless others who wanted to know
the real truth about why there was a problem.

- Rob
 

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Grüne Hölle Junkie
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Just thought of something off the wall...
What if you just removed the reed switch from the clutch cylinder and attached a small electomagnet to it? This electomagnet could be wired up to the ignition so that it only gets power when the ignition is on. Then you simply put a momentary push button switch inbetween the electromagnet and its power source from the ignition. Then, to start your car, hold the button down and turn the ignition switch.
I understand that if you just attach a permanent magnet to the clutch switch that you would lose your cruise control. But if you had this setup, the clutch switch would just be closed during starting and then it would be open for normal operation. This seems cheaper and a bit easier that replacing the clutch cylinder and making your own harness for it.
...just a thought of mine. this is what i think i will try because the parts can be found cheap at any Radio Shack
 

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Okay, Im bumping this because there have been alot of threads started asking how to deal with the new style master clutch cylinder. This is something I have been thinking about doing lately, but I have been too lazy so far. So, has anyone done the re-wiring of the old switch as Rob talks about above and do you have part #s or even a diagram of how the wiring was done?


:bump: :bump: :bump:
 

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E46 clutch switch bypass

It's not very difficult to bypass the Clutch Switch in order to add a Clutch Stop.

As stated in the post, the E46 from 03/2001 incorporated a magnetic sense clutch switch that replaces both, the clutch start interrupt switch and the cruise control interrupt switch. There are four (4) wires that go to the switch on the clutch hydraulic cylinder with the following values.

Connector position 1. Brown/Black = Ground
2. Gray = Cruise Control Interrupt
3. Vio/Yellow = 12 Volts
4. Blue = Clutch/Start Interrupt
or Blue/Brown

To bypass the Clutch/Start function, cut the Blue (or Blue Brown) wire
to the switch and splice it into the 12 Volt Vio/Yellow wire. Do not cut the Vio/Yellow wire. The Blue wire at the switch will not be used.

This way, Cruise Control will still function normally and a Clutch stop can be used at any height.


wire to the switch
 

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Connector position 1. Brown/Black = Ground
2. Gray = Cruise Control Interrupt
3. Vio/Yellow = 12 Volts
4. Blue = Clutch/Start Interrupt
or Blue/Brown

To bypass the Clutch/Start function, cut the Blue (or Blue Brown) wire
to the switch and splice it into the 12 Volt Vio/Yellow wire.

This way, Cruise Control will still function normally and a Clutch stop can be used at any height.
I have 1/2004 production model and I have the following wires:
  1. Brown with black
  2. Blue with grey or brown hard to tell
  3. Violet with yellow
  4. Blue with black

I am guessing splice the Blue with Black to the Violet with yellow.

Can anyone confirm?

Thanks,
 

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It's not very difficult to bypass the Clutch Switch in order to add a Clutch Stop.

As stated in the post, the E46 from 03/2001 incorporated a magnetic sense clutch switch that replaces both, the clutch start interrupt switch and the cruise control interrupt switch. There are four (4) wires that go to the switch on the clutch hydraulic cylinder with the following values.

Connector position 1. Brown/Black = Ground
2. Gray = Cruise Control Interrupt
3. Vio/Yellow = 12 Volts
4. Blue = Clutch/Start Interrupt
or Blue/Brown

To bypass the Clutch/Start function, cut the Blue (or Blue Brown) wire
to the switch and splice it into the 12 Volt Vio/Yellow wire. Do not cut the Vio/Yellow wire. The Blue wire at the switch will not be used.

This way, Cruise Control will still function normally and a Clutch stop can be used at any height.


wire to the switch

Did anyone tried this? Any results?
 

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I have 1/2004 production model and I have the following wires:
  1. Brown with black
  2. Blue with grey or brown hard to tell
  3. Violet with yellow
  4. Blue with black

I am guessing splice the Blue with Black to the Violet with yellow.

Can anyone confirm?

Thanks,
My 2001 325it has the same color combo as your '04. I took the blue with BLACK stripe and connected it to the violet with yellow. Do as the original poster said, by cutting the blue with black wire and splice it to the purple with yellow but DO NOT cut the purple with yellow wire from the small plug. See the picture on this posting to see how the OP did it. I did it today on my wagon and it now starts with the clutch out. The cruise control work as it should and if you push the clutch in while cruise is engaged, the cruise control releases as it should.
 

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I have a 2002 E46 M3, did the magnetic clutch switch bypass as outlined in "jorgmumster's" post #8 above, worked perfectly!!! thanks! (wire color's matched his written description). Thanks Jorg! If the shaft on the UUC bigboy was any longer, I'd probalby need to cut it. (damn near perfect)
 

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IMO an easier and better solution for disabling the interlock would be to just code it out. Using NCS Expert, load the EWS module and set "PARK/NEUTRAL_EINGANG" to nicht_aktiv
This^^

You can also use PA Soft in case you're not familiar with NCS.
 
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